Use of the Morlet mother wavelet in the frequency-scale domain decomposition technique for the modal identification of ambient vibration responses. (October 2017)

• Record Type: Journal Article
• Authors: Le, Thien-Phu
• Is Part Of: Mechanical systems and signal processing. Volume 95(2017)
• Page Start: 488
• Page End: 505
• Publication Date: 2017-10
• Subjects: Modal identification -- Wavelet transform -- Frequency-scale domain -- Ambient vibration -- Power spectral density -- Singular value decomposition -- Morlet mother wavelet -- Regressive mother wavelet; Structural dynamics -- Periodicals; Vibration -- Periodicals; Constructions -- Dynamique -- Périodiques; Vibration -- Périodiques; Structural dynamics; Vibration; Periodicals; 621
• DOI: 10.1016/j.ymssp.2017.03.045
• Languages: English
• ISSNs: 0888-3270

Abstract

Highlights: Frequency-scale domain decomposition method based on the Morlet mother wavelet. Identification of modal parameters from local maxima in frequency-scale plane. Validation using numerical examples and a laboratory test. Abstract: The frequency-scale domain decomposition technique has recently been proposed for operational modal analysis. The technique is based on the Cauchy mother wavelet. In this paper, the approach is extended to the Morlet mother wavelet, which is very popular in signal processing due to its superior time-frequency localization. Based on the regressive form and an appropriate norm of the Morlet mother wavelet, the continuous wavelet transform of the power spectral density of ambient responses enables modes in the frequency-scale domain to be highlighted. Analytical developments first demonstrate the link between modal parameters and the local maxima of the continuous wavelet transform modulus. The link formula is then used as the foundation of the proposed modal identification method. Its practical procedure, combined with the singular value decomposition algorithm, is presented step by step. The proposition is finally verified using numerical examples and a laboratory test.